An embryo's development won't go backwards Luv. It can and will arrest and go no further or it will slow down, but it won't go backwards.
I'm a bit confused. Did the technician today say your blasty was a 4AA and a different technician yesterday say it was a 3AA?? The TE/ICM grades haven't changed and are still AA which is the best of the best, only the expansion grade is in question.
Hmmmm.....will give an opinion on that when you clarify for me